The core of the event data recorder is shown here first. It also contains data on the number of occupants, whether they were wearing seat belts and 250 ms after the collision, acceleration data is recorded in the transverse and longitudinal directions.
These are the recordings of the accident data memory 5 seconds BEFORE the accident. In the left-hand column, the time intervals at which measurements were taken are shown in half-second increments. This means that values were written from the vehicle to the memory at half-second intervals.
What you can see here is that the accelerator pedal was not depressed until 1.5 seconds before the accident. After that, values are entered that go up to 30%, 90% and then 100%.
The brake, service brake activation, shows with the value off that it was not used the whole time.
Steering input describes the steering wheel angle of the vehicle. Before the accident, the angle ranges from 0 to 18.
There are further detailed articles on these three topics.
The fact that there are no values in Engine RPM Electrical Engine 1 is an error. These values can probably still be found in the hex dump of the document. The complete accident data memory can be found here. Anyone who would like to help me convert the 13 bit hex values is welcome to contact me. We have already been able to decode some areas of the hex block and have marked them. We will go into these later in the Overflow chapter.
Reference is also made here to another event data recorder of an identical vehicle, which shows a similar pattern with regard to steering wheel data, brake and accelerator pedal position.
When is a crash detected?
To trigger the writing of an accident data memory, there must be a deceleration of 8 km/h within 150 ms in the longitudinal or transverse direction. This description is stored in the document itself.
If the car approached the queue of cars at 6 km/h as I described, it is quite possible that the first contact with the SUV did not trigger the writing of the accident data memory at all, but that it was only written later, e.g. when the vehicles collided with the Sprinter.
There are also some other injured parties in the group who do not have an event data recorder because the deceleration at the time of the collision was less than 8 km/h.